1. Field of the Invention
The present invention relates to a photosensitive member-protective shutter for use in electrophotographic apparatuses and/or a shielding member for the photosensitive member-protective shutter.
2. Description of the Prior Art
In an electrophotographic apparatus, the surface of a photosensitive member is first statically charged by a charger and is then exposed so that an electrostatic latent image is formed on the surface of the photosensitive member. The latent image is developed by toner to form a toner image, the toner image being then transferred onto a recording medium. Finally, the surface of the photosensitive member is subjected to electrostatic discharge so that any residual electrostatic latent image on the surface of the photosensitive member is removed to complete an image forming operation.
As such image forming operation is repeated with the electrophotographic apparatus, the charger is subject to accumulation of statically produced products, such as ozone and nitrogen oxides (NOx) produced through corona discharge of the charger, or nitrates produced through adsorption of nitrogen oxide (NOx) onto the charger, during the image-forming process. Since the charger is disposed in opposed relation to the photosensitive member, the statically produced products accumulated on the charger may move close to or migrates to the surface of the photosensitive member during stopping of the movement of the photosensitive member, the statically produced product thus degrading the photosensitive member.
The degraded portion of the photosensitive member is liable to moisture or water deposition, which leads to low electrical resistance, thus causing a charge flow. This results in image flowing. This tendency becomes more pronounced under high-temperature and high-humidity conditions in particular.
If the surface of the photosensitive member is soft, portions of the photosensitive member which have been deteriorated due to statically produced products thereon may be scraped down by means of a blade simultaneously when toner remaining on the surface of the photosensitive member after transfer is removed. In such a case the above noted problem is not so much noticeable.
However, if the surface of the photosensitive member is substantially hard, it is not easy to scrape down the deteriorated portions by a blade or the like, in which case once the photosensitive member is deteriorated by the statically produced products, it is difficult to recover the degraded portions to normal states, and this poses a serious problem.